Various mechanisms have been disclosed in heretofore issued patents which provide for adjustment of the air dilution value of filter cigarettes, but these mechanisms are not without certain disadvantages. While many complicated mechanisms have been disclosed, the simpler mechanisms generally involve making one or more openings through a substantially air-impermeable filter plug wrap and the overlying substantially air-impermeable tipping paper and one or more corresponding openings in a sleeve which is placed over the tipping paper and which is then either rotated or moved axially to select the degree to which the two sets of openings are in registry.
Among the problems associated with such a mechanism are that the sleeve may be inadvertently removed from the mouth end of the cigarette by the smoker and not readily replaced, and that when dilution is desired, the registry between the two sets of openings may be inadvertently destroyed by a slight axial movement of the sleeve. Accordingly, th dilution, once set by the smoker, is not insured of any degree of consistency. Yet another problem associated with a number of prior devices is that they have not been readily adaptable to a high rate of production on conventional cigarette making machinery.
Accordingly, it is an object of the present invention to provide an improvement on such variable dilution filter cigarettes which can be readily manufactured on conventional cigarette making equipment.